Balian S J, Kunze M B A, Mohammady M H, Morley G W, Witzel W M, Kay C W M, Monteiro T S
Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
Phys Rev B Condens Matter Mater Phys. 2012 Sep 21;86(10). doi: 10.1103/PhysRevB.86.104428.
We present pulsed electron-nuclear double resonance (ENDOR) experiments which enable us to characterize the coupling between bismuth donor spin-qubits in Si and the surrounding spin-bath of (29)Si impurities which provides the dominant decoherence mechanism (nuclear spin diffusion) at low temperatures (< 16 K). Decoupling from the spin-bath is predicted and cluster correlation expansion simulations show near-complete suppression of spin diffusion, at optimal working points. The suppression takes the form of sharply peaked divergences of the spin diffusion coherence time, in contrast with previously identified broader regions of insensitivity to classical fluctuations. ENDOR data shows anisotropic contributions are comparatively weak, so the form of the divergences is independent of crystal orientation.
我们展示了脉冲电子-核双共振（ENDOR）实验，这些实验使我们能够表征硅中铋施主自旋量子比特与周围（29）Si杂质自旋浴之间的耦合，该自旋浴在低温（<16 K）下提供了主要的退相干机制（核自旋扩散）。预测了与自旋浴的解耦，并且团簇关联展开模拟表明，在最佳工作点，自旋扩散几乎完全被抑制。与先前确定的对经典涨落不敏感的更广泛区域相比，这种抑制表现为自旋扩散相干时间的尖锐峰值发散形式。ENDOR数据表明各向异性贡献相对较弱，因此发散形式与晶体取向无关。
